In the current broadcasting system, media transport schemes of an MPEG-2 TS (Moving Picture Experts Group-2 Transport Stream) scheme and an RTP (Real-time Transport Stream) scheme are widely used. In these schemes, when attempting to cooperatively operate broadcasting and communication, various limitations arise. Therefore, MMT (MPEG Media Transport) is proposed as a new media transport scheme assuming the use of a variety of networks by utilizing MPEG.
In an MMT transmission system adopting the MMT, in order to secure confidentiality of an MMTP (MPEG Media Transport Protocol) packet which is to be transmitted, scrambling is applied to the MMTP packet. A payload part of the MMTP packet, excluding a control message, is the scrambling range.
In some cases, the MMT transmission system builds up a redundant configuration so that its function is maintained even in the case where a failure, etc. has occurred. A switching device provided on the MMT transmission system is desired to perform switching as seamlessly as possible between a main system and a redundant system upon, for example, maintenance. In the case of seamlessly switching between the main system and the redundant system, it is necessary for the switching device to identify an MPU (Media Processing Unit) boarder to identify a switching point. However, in order to identify the MPU boarder in the MMTP packet to which scrambling has been applied, the payload in the MMTP packet needs to be analyzed. Therefore, there has been a problem that the MMTP packet to which scrambling has been applied needs to be descrambled.